Air injection system for engine exhaust gases

ABSTRACT

Apparatus for supplying supplemental air to exhaust gases exiting exhaust ports in a wall of a cylinder head of a multi-cylinder internal combustion engine and entering runners of an exhaust manifold through runner inlet ports aligned with the respective exhaust ports. An air injection plate is interposed between the cylinder head and the manifold. The air injection plate has openings aligned and registering with the respective exhaust ports and runner inlet ports. A fitting directs the supplemental air to the air injection plate openings to combine with the exhaust gases passing from the exhaust ports to the runner inlet ports.

FIELD OF THE INVENTION

[0001] This invention relates to apparatus for supplying supplementalair to exhaust gases exiting from the cylinder head of an internalcombustion engine.

BACKGROUND OF THE INVENTION

[0002] To reduce tailpipe non-methane hydrocarbon (NMHC) emissionsduring engine warm-up, supplemental air is often added to the exhaustgases. The supplemental air induces combustion in the exhaust manifold.The induced combustion burns excess fuel, reducing NMHC emissions andcreating heat which transfers to the catalyst substrate. The catalyst isbrought up to a functional temperature faster by this heat transfer,thus further decreasing cumulative NMHC tailpipe emissions. CumulativeNOx and CO are also reduced due to faster catalyst warm-up.

[0003] To supply the supplemental air, an air pump is employed. Thesupplemental air is transferred to the stream of exhaust gases as closeto the engine exhaust valve as possible to maximize combustion in themanifold. On many engines, passages for supplemental air are designedinto the cylinder head. While such air passages are the ideal way tointroduce supplemental air, they are generally very expensive to addunless they are included in the initial cylinder head design. Whenadding a supplemental air system to an existing engine, an alternativemethod of supplying the supplemental air is needed.

SUMMARY OF THE INVENTION

[0004] In accordance with the present invention, apparatus is providedto supply supplemental into the exhaust stream close to the exhaustvalve but without significant modification of the cylinder head. An airinjection plate at the interface between the cylinder head and themanifold has openings aligned with exhaust ports of the cylinder headand runner inlet ports of the manifold.

[0005] A gasket forms a seal between the air injection plate and a wallof the cylinder head. The gasket has an aperture which encompasses morethan one of the openings in the air injection plate. Supplemental air isintroduced to a space or chamber within the aperture defined between theair injection plate and the cylinder head wall. The supplemental air issupplied to a fitting installed in an exhaust manifold inlet flange, andpasses from the fitting into the chamber. Preferably the air injectionplate has grooves defining paths for the supplemental air which lead tothe openings in the air injection plate. The supplemental air at theopenings in the air injection plate enters the exhaust stream passingfrom the exhaust ports of the cylinder head into the inlet ports of therunners of the manifold.

[0006] One object of this invention is to provide apparatus forsupplying supplemental air into an exhaust stream having the foregoingfeatures and capabilities.

[0007] Another object is to provide apparatus for supplying supplementalair which is composed of a relatively few simple parts, is rugged anddurable in use, and is capable of being inexpensively manufactured andinstalled.

[0008] Further areas of applicability of the present invention willbecome apparent from the detailed description provided hereinafter. Itshould be understood that the detailed description and specificexamples, while indicating the preferred embodiment of the invention,are intended for purposes of illustration only and are not intended tolimit the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will become more fully understood from thedetailed description and accompanying drawings, wherein:

[0010]FIG. 1 is an exploded view in perspective of apparatus constructedin accordance with this invention.

[0011]FIG. 2 is an elevational view of a gasket forming part of theapparatus shown in FIG. 1.

[0012]FIG. 3 is an elevational view of an air injection plate formingpart of the apparatus shown in FIG. 1. The side of the air injectionplate shown in FIG. 3 is opposite the side shown in FIG. 1.

[0013]FIG. 4 is an elevational view of another gasket forming part ofthe apparatus shown in FIG. 1.

[0014]FIG. 5 is a sectional view of a portion of the apparatus, taken onthe line 5—5 in FIG. 3.

[0015]FIG. 6 is a sectional view taken on the line 6—6 in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] Referring now more particularly to the drawings, a cylinder head10 of an internal combustion engine 11 has a plurality of laterallyspaced apart exhaust ports 12, 14, 16 and 18 extending through a flatouter wall 20 of the cylinder head. A manifold 22 has a plurality ofrunners 24, 26, 28 and 30 leading to a main manifold outlet 32. Themanifold runners have runner inlet ports 34, 36, 38 and 40 aligned andregistering with the respective exhaust ports 1218. Exhaust gases fromthe cylinder head flow into the runners and from the runners to the mainoutlet 32 where such gases may be routed through a catalytic converter.

[0017] An integrated air injection rail (I.A.I.R.) 42 is placed betweenthe wall 20 of the cylinder head and the inlet ports 34-40 of themanifold runners. The I.A.I.R. 42 consists of an air injection plate 44and gaskets 46 and 48 on opposite sides of the air injection plate.

[0018] The air injection plate 44 has openings 50, 52, 54 and 56 alignedand registering with the respective exhaust ports 12-18 in the cylinderhead wall 20 and inlet ports 34-40 of the runners.

[0019] The gasket 46 forms a seal between the cylinder head wall 20 andone face of the air injection plate 44. An aperture 58 in the gasket 46has a peripheral edge 60 encompassing the exhaust ports 12 and 14 andthe registering openings 50 and 52 in the air injection plate 44. Aspace or chamber 62 (FIG. 5) in defined between the face of the airinjection plate 44 and the cylinder head wall 20, within the peripheraledge 60 of the aperture 58. The gasket 46 is very thin, preferably onthe order of about 0.25 mm so that the chamber 62 is correspondinglythin. The thickness of the gasket 48 is also preferably about 0.25 mm.

[0020] An air fitting 64 mounted in a flange 66 of the manifold 22communicates with the chamber 62 through a hole 68 in the gasket 48 anda hole 70 in the air injection plate 44 to introduce supplemental airfrom an air pump (not shown) into the chamber. Grooves 74 (FIGS. 3 and5) in the face of the air injection plate 44 extend from the hole 70 tothe two openings 50 and 52 in the air injection plate. The grooves 74have branches 76 which open into the openings 50 and 52 at severalspaced points to facilitate the flow of supplemental air to theopenings.

[0021] A second aperture 80 in the gasket 46 has a peripheral edge 82encompassing the exhaust ports 16 and 18 and registering openings 54 and56 in the air injection plate 44. A space or chamber 84 is definedbetween the face of the air injection plate 44 and the cylinder head 20,within the peripheral edge 82 of the aperture 80. An air fitting 86 ismounted in a flange 88 of the manifold 22 and communicates with thechamber 84 through a hole 90 in the gasket 48 and a hole 92 in the airinjection plate 44 to introduce supplemental air from an air pump (notshown) into the chamber 84. Grooves 94 in the face of the air injectionplate 44 extend from the hole 92 to the two openings 54 and 56 in theair injection plate. The grooves 94 have branches 96 which open into theopenings 54 and 56 at several spaced points to facilitate the flow ofsupplemental air to the openings.

[0022] The air injection plate 44 is preferably about 3 mm in thickness.The depth of the grooves is preferably about 2 mm. The grooved airinjection plate 44 may be formed by any suitable means, such, forexample as coining, forging, or by using sintered metal.

[0023] The grooves 74 and 94 enable a free flow of supplemental air tothe openings 50-56 and are very desirable because of the extremethinness of the chambers 62 and 84.

[0024] The gasket 48 has openings 100, 102, 104 and 106 aligned andregistering with the respective openings 50-56 in the air injectionplate 44 and the runner inlet ports 34-40. The gasket forms a sealbetween the manifold 22 and the air injection plate 44 around the runnerinlet ports 34-40 and the openings 50-56 in the air injection plate.

[0025] Fasteners 110 secure together the cylinder head 10, manifold 22,air injection plate 44 and gaskets 46 and 48.

[0026] The supplemental air delivered to the openings 50-56 of the airinjection plate 44 combines with the exhaust stream passing from theexhaust ports 12-18 of the cylinder head 20 into the inlet ports 34-40of the runners 24-30 of the manifold 22.

[0027] The description of the invention is merely exemplary in natureand, thus, variations that do not depart form the gist of the inventionare intended to be within the scope of the invention. Such variationsare not to be regarded as a departure from the spirit and scope of theinvention.

What is claimed is:
 1. Apparatus for supplying supplemental air toexhaust gases exiting exhaust ports in a wall of a cylinder head of amulti-cylinder internal combustion engine and entering runners of anexhaust manifold through runner inlet ports aligned with the respectiveexhaust ports, comprising: an air injection plate interposed between thecylinder head and the manifold, said air injection plate having openingsaligned and registering with the respective exhaust ports and runnerinlet ports, and means for directing the supplemental air to the airinjection plate openings to combine with the exhaust gases exiting theexhaust ports and entering the exhaust manifold through the runner inletports.
 2. The apparatus of claim 1, wherein said means for directing thesupplemental air includes a fitting for directing air into a hole insaid air injection plate, and grooves in one surface said plateextending from said hole to a plurality of the openings in said plate,said grooves defining air paths from said hole to said plurality of theopenings.
 3. The apparatus of claim 1, wherein said means for directingthe supplemental air to the injection plate openings includes a gasketsealing between one surface of said air injection plate and the wall ofthe cylinder head, said gasket provided with an aperture having amarginal edge encompassing a plurality of said openings in said plate, achamber defined by said one surface of said plate and said wall of thecylinder head within the marginal edge of the aperture, and means forintroducing supplemental air into said chamber.
 4. The apparatus ofclaim 3, wherein said means for introducing supplemental air into saidchamber includes an air fitting carried by said exhaust manifold, saidfitting opening into said chamber through a hole in said air injectionplate.
 5. The apparatus of claim 4, wherein said one surface of saidplate has grooves defining air paths leading from the hole in said airinjection plate to said respective plurality of openings.
 6. Theapparatus of claim 5, wherein said grooves have branches which open intoeach of said plurality of openings at a plurality of spaced points. 7.The apparatus of claim 6, further including a second gasket sealingbetween a second surface of said plate and said manifold having openingsaligned and registering with the openings in said plate and the runnerinlet ports.